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Andrew_L26

L28 F54 P90A, Flattop Pistons?

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Hi all, So I've found out my motor is an L28 with the F54 block, P90a Head and flattop pistons. Seems like an odd combination, anyone know what this combination would be good for?

I'm currently giving the British SU's an overhaul and I'm wondering what kind of power I could expect to push with a good tune on them?

 

Cheers,

Andrew

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it will be fine in both NA and turbo application, dished pistons with a P90 head will give you under 8.1.1 compression with flatops its around 8.5.1 comp from memory which is fine for both applications

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I'll tell you how the turbo setup works out with the same combination. Booked a week off in September to finally assembled all the bits Ive acquired.

 

Valve train noise should be really quite if you have a hydraulic lifter setup. Take off the valve cover and you should be lacking the valve adjusters that my P90 has.

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I'll tell you how the turbo setup works out with the same combination. Booked a week off in September to finally assembled all the bits Ive acquired.

 

Valve train noise should be really quite if you have a hydraulic lifter setup. Take off the valve cover and you should be lacking the valve adjusters that my P90 has.

I decided to take my rocker cover of to polish and take some photos. Any ideas?

 

post-103470-0-66154300-1471322053_thumb.png

Edited by Andrew_L26

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They are the regular ones. To answer your original question the P90 heads generally came with flat tops as the combustion chambers are bigger and had a lower compression ratio. It will be fine with twin SUs and will make about the same as any stock L28 depending on the condition.

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Was there actually any Australian delivered Datsun with a factory P90 head? A lot from what I've read in the last few months point to it being a Turbo only head.

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Wrong Jake, P90 headed engines are all dished piston, they were made like that, so that factory could either fit it with the turbo setu, or fit it as N/A, to meet whatever missions requirements for that country, usually USA.

Used two different ECU's and two different distributors.

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I just did a quick google and that seems to be an american thing F54 with P79 head had flat tops. 

 

I thought P90/F54 was available in Patrols at some stage. Probably wrong about that too.

Edited by d3c0y

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Was there actually any Australian delivered Datsun with a factory P90 head? A lot from what I've read in the last few months point to it being a Turbo only head.

Early 1980 Patrol's had L28s some with P90 heads.

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I thought that the P90a head had hydraulic lifters. Did we ever get turbo L28's in Australia and if so what were their configurations.

 

Andrew

Edited by Andrew_L26

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